In recent years, power generating machines such as power generation turbines, boilers, etc. tend to be used under high temperature and high pressure to improve their thermal efficiency. Therefore, high Cr steels (e.g., 9Cr steel and 12Cr steel) having superior strength at high temperature have been developed as constituting materials of the power generating machines.
Welding is useful for manufacturing the power generating machines, and there have been developed high Cr steel welding technologies. For example, there is developed a technology to improve stability of arc at a time of welding by containing rare earth metals into a welding material for MAG welding of high Cr steels.
But, it is not necessarily easy to produce the above-described welding material when it contains a preferable rare earth metal content, and its cost becomes high in comparison with the general high Cr steel MAG welding material, and it is difficult to secure the narrow gap welding quality.